/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.ComponentModel;

namespace Spring.Core;

/// <summary>
/// Provides additional data for the <c>PropertyChanged</c> event.
/// </summary>
/// <remarks>
/// <p>
/// Provides some additional properties over and above the name of the
/// property that has changed (which is inherited from the
/// <see cref="System.ComponentModel.PropertyChangedEventArgs"/> base class).
/// This allows calling code to determine whether or not a property has
/// actually changed (i.e. a <c>PropertyChanged</c> event may have been
/// raised, but the value itself may be equivalent).
/// </p>
/// </remarks>
/// <seealso cref="System.ComponentModel.PropertyChangedEventArgs"/>
[Serializable]
public class PropertyChangeEventArgs : PropertyChangedEventArgs
{
    private object oldValue;
    private object newValue;

    /// <summary>
    /// Create a new instance of the
    /// <see cref="Spring.Core.PropertyChangeEventArgs"/> class.
    /// </summary>
    /// <param name="propertyName">
    /// The name of the property that was changed.</param>
    /// <param name="oldValue">The old value of the property.</param>
    /// <param name="newValue">the new value of the property.</param>
    public PropertyChangeEventArgs(
        string propertyName, object oldValue, object newValue) : base(propertyName)
    {
        this.oldValue = oldValue;
        this.newValue = newValue;
    }

    /// <summary>
    /// Get the old value for the property.
    /// </summary>
    /// <seealso cref="System.ComponentModel.PropertyChangedEventArgs.PropertyName"/>
    public object OldValue
    {
        get { return oldValue; }
    }

    /// <summary>
    /// Get the new value of the property.
    /// </summary>
    /// <seealso cref="System.ComponentModel.PropertyChangedEventArgs.PropertyName"/>
    public object NewValue
    {
        get { return newValue; }
    }
}
